Labile organic carbon (LOC) is the most active fraction of soil organic carbon (SOC) with rapid turnover rates, and has been suggested as sensitive indicator of SOC pool under global change. However, the knowledge of LOC pools in coastal wetland soils and their implication for soil carbon reservoir are still scarce. We characterized LOC in soils from two coastal wetlands using cold water extractable carbon (CWC), hot water extractable carbon (HWC), and acid hydrolysable carbon (AHC). Our results indicated that SOC and its labile fractions are higher in Guangrao than that in Changyi. CWC comprised about 24.09-34.86% of SOC for Guangrao and 1.54-2.43% for Changyi. The HWC content was generally higher than CWC, and HWC in Changyi contributed higher proportion to SOC compared with Guangrao wetland. The AHC represented much higher proportion of SOC about 45.94-50.11% in Guangrao and 60.38-65.08% in Changyi, respectively. CWC, HWC and AHC were significantly correlated with each other in profile CB1. Poor correlation among LOC and SOC was observed in GA1, GA2 and CB2. Differences in vegetation and hydrological condition should be considered for obtaining accurate carbon calculation. Relative high proportion of LOC suggests these wetlands might be particularly vulnerable to a warming environment.